Supercharged power tongs

Power tongs for making up or breaking apart pipe joints having a longitudinal axis comprising:

• an upper tong and lower tong lying in spaced apart horizontal planes having on each tong body a pair of opposed gripping jaws disposed in facing relation and synchronously movable along a linear trace, respectively, for gripping engagement with upper and lower drill pipe joints, respectively;
• means swivelly connecting and guiding said upper and lower tongs for relative angular movement about a vertical axis by an actuator, said means including an arc ram with arc grooves thereon attached to said lower tong body and a supporter mounted floatably in radial direction on said upper tong and provided with at least three rollers being able to roll in an arc groove of said arc ram, thereby to swivelly connect said upper and lower tongs and to guide the relative angular movement;
• a pressurized fluid powered multistage torque-generating unit with an assist fluid cylinder pivotally connected with said upper and lower tongs respectively, said unit being able to output a torque to swivel said tongs in relation to each other over a limited angle displacement around the longitudinal axis of the pipe joints being gripped, whereby the drill pipe joint may be made up or broken apart, and being able to offer a larger torque at the beginning of an unscrewing operation, when said upper and lower tongs are in coincident position, said unit being able to rotate about a vertical axis by 180 degrees, said unit comprising a torqueing fluid cylinder offering make-up torques, an assist fluid cylinder coaxially mounted with said torqueing cylinder for the requirement of increasing torque during breaking apart and a torque-selecting device, either the chamber of said torqueing cylinder or the chamber of said assist fluid cylinder being divided into rod chamber which is at the front of said chamber and rod-less chamber which is at the rear of said chamber, the piston rod of said assist fluid cylinder having an axial fluid passage communicated with said rod-less chamber of said assist fluid cylinder, the free end of the piston rod of said assist cylinder entering the rod-less chamber of said torqueing cylinder from the rear end of said torqueing cylinder to contact the the piston of said torqueing cylinder, the rod chambers of said torqueing cylinder and said assist fluid cylinder being mutually fluid communicated and so being their rod-less chambers, and fluid entering into and exiting from the rod-less chambers of said assist fluid cylinder through the rod-less chamber of said torqueing cylinder, an opening at the free end of the piston rod of said assist fluid cylinder and the axial fluid passage in the piston rod of said assist fluid cylinder, said piston rod of said torqueing cylinder being pivotally mounted in a bore-hole at the rear end of said lower tong by means of a ball bearing, said torqueing cylinder being swivelly connected with horizontal lug flanges on a suspension frame through horizontal lug pivots on both sides of said cylinder body, an upright axle on said suspension frame, orthogonal with and a certain distance apart from the axis of said horizontal lug flanges, being pivotally mounted in a bore-hole at the rear end of said lower tong, said upright axle having an eccentric crown key on upper end face thereof, said torque-selecting device consisting of a cock actuated by said eccentric crown key, said cock enabling said assist fluid cylinder to engage in or release from working state;
• a supercharging gripping device disposed on each tong to enable each said pair of opposed gripping jaws first move towards each other along a linear trace to grip pipes speedily and then by means of a supercharged fluid cylinder to enlarge the gripping force to get hold of said pipes firmly without raising the pressure of fluid system, each said pair of opposed gripping jaws realizing synchronous movement by means of a synchronizing mechanism;
• a manual-pneumatic pull-in locating device mounted in parallel on the upper tong for aligning said tongs with and pulling over them together to said pipes;
• and
• a program controlled system enabling gripping operation and making up or break-apart operation to be carried out automatically according to a procedure predetermined.

Power tongs for making up or breaking apart pipe joints having a longitudinal axis comprising:

• an upper tong and a lower tong lying in spaced apart horizontal planes having on each tong body a pair of opposed gripping jaws disposed in facing relation and synchronously movable along a linear trace, respectively, for gripping engagement with upper and lower drill pipe joints, respectively;
• means swivelly connecting and guiding said upper and lower tongs for relative angular movement about a vertical axis by an actuator;
• a pressurized fluid powered multi-stage torque-generating unit with an assist fluid cylinder pivotally connected with said tongs respectively, said unit being able to output a torque to swivel said tongs in relation to each other over a limited angle displacement around the longitudinal axis of the pipe joints being gripped to make up or break apart said pipe joints, and being able to offer a bigger torque at the beginning of an unscrewing operation;
• a supercharged gripping device disposed on each tong whereby said each pair of opposed gripping jaws may first move towards each other along a linear trace to grip pipes speedily and then by means of a supercharged fluid cylinder enlarge the gripping force to get hold of said pipes firmly without raising the pressure of fluid system, each said pair of gripping jaws realizing synchronous movement by means of synchronizing mechanism;
• a manual-pneumatic pull-in locating device mounted in parallel on said upper tong for aligning said tongs with and pulling them over to said pipes;
• and
• a program controlled system enabling gripping operation and make-up or break-apart operation to be carried out according to a procedure predetermined;
• wherein said upper and lower tong bodies are similarly shaped and are substantially plate-like members each with a notch in the middle of its front side, said supercharged gripping device disposed on each tong includes a rapid pregripping and supercharging system consisting of two hydraulically powered gripping cylinders of identical configuration and a supercharger cylinder, an adaptive self-adjusting device of tong dies and tong dies release control device consisting of a hand operated hydraulic lock, said gripping cylinder has two entrance and exit fluid openings communicating with two chambers therein, two gripping cylinders are disposed coaxially and symmetrically on both sides of said notch of each of said tong bodies respectively, the cylinder housings of said two gripping cylinders being movable while the pistons and the piston rods thereof being unmovable, said movable cylinder housings are connected to said tong dies by means of said adaptive self-adjusting device of tong dies, a supercharger cylinder disposed at the back or other proper position of said tong body is connected with said two gripping cylinders through fluid pipes respectively, and said synchronizing mechanisms enabling synchronized extending or retracting movement of said tong dies.

Power tongs for making up or breaking apart pipe joints having a longitudinal axis comprising:

• an upper tong and a lower tong lying in spaced apart horizontal planes having on each tong body a pair of opposed gripping jaws disposed in facing relation and synchronously movable along a linear trace, respectively, for gripping engagement with upper and lower drill pipe joints, respectively;
• means swivelly connecting and guiding said upper and lower tongs for relative angular movement about a vertical axis by an actuator;
• a pressurized fluid powered multi-stage torque-generating unit with an assist fluid cylinder pivotally connected with said upper and lower tongs respectively, said unit being able to output a torque to swivel said tongs in relation to each other over a limited displacement angle around the longitudinal axis of the pipe joints being stripped whereby the drill pipe joint may be make up or broken apart, and being able to offer a larger torque at the beginning of unscrewing operation;
• a supercharged gripping device disposed on each tong whereby said each pair of opposed gripping jaws may first move towards each other along a linear trace to grip pipes speedily and then by means of a supercharged fluid cylinder enlarge the gripping force to get hold of said pipes firmly without raising the pressure of fluid system, each said pair of gripping jaws may realize synchronous movement by means of a synchronizing mechanism;
• a manual-pneumatic pull-in locating device mounted in parallel said upper tong for aligning said upper and lower tongs with and pulling them over to said pipes;
• a program controlled system enabling gripping operation and make-up or break-apart operation to be carried out according to a procedure predetermined;
• wherein said manual-pneumatic pull-in locating device includes a back and forth movable ram body provided with horizontal pneumatically powered gripping jaws at the front and having longitudinal guiding rails, a hauling air cylinder being mounted on said upper tong with guiding rollers on both sides, one end of the piston rod of said air cylinder being connected with said ram body, said ram body can slide on said guiding rollers by means of its guiding rails, the centre of said pneumatically powered gripping jaws is aligned with the centres of said two pairs of gripping jaws of said upper and lower tongs as said ram body fully retracted.